8.2.1 Identify different world energy sources. Students should be able to recognize those sources associated with CO2 emission. Students should also appreciate that, in most instances, the Sun is the prime energy source for world energy.
For more information click here :) Also refer to Giancoli pg. 466-467
Fossil Fuel
Fossil Fuels are naturally occurring fuels formed by the remains of plants and animals from millions of years ago. They provide most of the world's energy supply. When burnt, fossil fuels release energy. They also produce: water, large amounts of carbon dioxide (CO2), carbon (soot), carbon monoxide (CO), sulphur dioxide (SO2), oxides of nitrogen, unburnt hydrocarbons and particulate matter. Therefore burning fossil fuels is a huge source of pollution.
Common Fossil fuels: Peat, coal, crude oil, oil shale, oil tar, natural gas
Refer to 8.3
Nuclear Power
There are two ways (nuclear reactions) to obtain nuclear energy: nuclear fusion and nuclear fission. Currently our technology allows us to safely use only nuclear fission. Nuclear reactions produce no greenhouse gases, but they release radioactivie substances which are highly dangerous.
Refer to 8.4.1-8.4.11
Renewable Resources
Solar Energy Solar energy comes from our sun which creates energy from nuclear fusion (mainly of hydrogen and helium). The sun provides 90% of the thermal energy needed to heat the Earth. We can directly harvest solar energy with passive solar energy cells and photovoltaic cells; both of these methods are pollution free. The sun is also indirectly responsible for a number of energy sources, both renewable and non-renewable:
Wind power, fossil fuels, wave power, biomass, food (chemical energy) etc.
Refer to 8.4.12-8.4.14
Wind Power Wind power is made possible by the sun.Wind occurs when currents of air move due to temperature differences. This type of power is also pollution free.
Refer to 8.4.18-8.4.20
Hydropower Hydropower makes use of gravity. Obtaining this type of energy is also pollution free. It will be explored with more details in section 8.4.16-17 and 8.4.22
by Jennifer
8.2.2 Outline and distinguish between renewable and non-renewable energy sources.
There is a very very good link on BBC about the types of energy. The third page is about Non-renewable energy and the fourth page is about renewable energy. go to GCSE Bitesize
The other pages are good too.
Anon-renewable energy source is one that is considered to be a temporary source that is depleted when it is used. (Nuclear energy could be considered a non-renewable resource however the finite amount of fissable material could last several thousand years at the current rate of usage so it is not considered a non-renewable resource. (according to the green book))
Non-renewable energy sources are for the most part fossil fuels. They are introduced in 8.2.1 above and discussed in 8.3. You can also check the green book and the following link which also has further links relating to non renewable resources. Non renewable energy sources
A natural resource qualifies as arenewable resource if it is replenished by natural processes at a rate comparable or faster than its rate of consumption by humans or other users. Renewable energy source is one that is permanent or one that can be replenished as it is used.
Renewable energy existing capacities, at end of 2006, from REN21[1] examples
Perpetual resources that are in no danger of being used in excess of their long-term availability i.e.
Solar radiation
Tides
Winds
Hydroelectricity
Some renwewable resources must be carefully managed to avoid exceeding the environments capacity to replenish them i.e.
Geothermal power
Fresh water
Timber
Biomass
Renewable sources being developed for commercial uses i.e.
Nuclear fusion
Solar Energy
Biomass
Wind energy
Tidal energy
Wave energy
Hydro-electric Energy
Geothermal Energy
Nuclear fusion is likely to be the energy source of the future but at this stage the reaction of the fusion elements can neither be contained nor controlled.
From Wikipedia: http://en.wikipedia.org/wiki/Renewable_energy
Above shows the comparison of total solar (left), wind and geothermal energy (center) resources compared to global energy consumption (right).
8.2.3 Define the energy density of a fuel. Energy density is measured in J kg–1 . Definition: amount of potential energy stored in a fuel per unit mass or per unit volume (measured per unit volume basically for pressurized gases). The
'energy stored' is considered to be chemical potential energy.
Energy Density of a Fuel = Chemical Potential Energy/Mass
This means that the higher energy density a fuel has, the more energy is stored for the same amount of mass.
Here are some common types of fuels and their energy densities. For more types of fuels and their (possibly inaccurate) energy densities click here.
8.2.4. Discuss how choice of fuel is influenced by its energy density. The values of energy density of different fuels will be provided.
Gravimetric Energy Density and Volumetric Energy Densities of different fuels
1 Watt second is 1 joules, so 1 Watt hour which is 3600 Watt second, would be 3600J and conversely 1J is 2.7778 ×10−4 watt hour
The following table is in Watt hour per kilogram (Wh/kg) and Watt per liter (Wh/l)
Type of fuel
Volumetric
Gravimetric
Fission of Uranium-235
4.7 x 1012 Wh/l
2.5 x1010 Wh/kg
Diesel
10,942Wh/l
13,762 Wh/kg
Gasoline
9,700 Wh/l
12,200 Wh/kg
Black Coal Solid
9444 Wh/l
6667Wh/kg
Black Coal Bulk
6278 Wh/l
6667Wh/kg
Liquified Natural Gas
7,216 Wh/l
12,100 Wh/kg
Hydrogen Peroxide (rocket fuel)
1,187 Wh/l
813 Wh/kg
Ethanol
6,100 Wh/l
7,850 Wh/kg
Methanol
4,600 Wh/l
6,400 Wh/kg
Ammonia
4,325 Wh/l
4,318 Wh/kg
Wood (varies with tyoe of wood and moisture content)
500 -900Wh/l
1,600 - 4,709 Wh/kg
Propane gas
28.1 Wh/l
13,900 Wh/kg
Propane liquid
7,500 - 6,600 Wh/l
13,900 Wh/kg
Compressed Air
17 Wh/l
34 Wh/kg
Intuitively, a higher energy density is favorable (more energy). By this yardstick, U-235 is the best source of energy. But there are practical considerations! Nuclear power stations are very expensive to build (especially with safety standards), and we must compare the energy release with the cost of its production (economics).
It has generally been found that fossil fuels are the most cost effective (by comparing cost of production with energy density).
By Tetsuya
8.2.5 State the relative proportions of world use of the different energy sources that are available. Only approximate values are needed. From Wikipedia: http://en.wikipedia.org/wiki/Image:World_energy_usage_width_chart.svg
This chart shows an approximation of the world's current energy usage.
From this we can see that Hydropower is the most popular source of renewable energy. Unfortunately, it can significantly damage its surroundings (see below). New technology may allow for better hydropower standards.
By Jennifer 8.2.6 Discuss the relative advantages and disadvantages of various energy sources.
The discussion applies to all the sources identified in sub-topics 8.2, 8.3 and 8.4.
Type of power
Advantages
Disadvantages
Nuclear Energy
l No emission of greenhouse gases and particulate matter l Large energy density l Extraction is less damaging to land than extracting fossil fuels l Does not release carbon dioxide
l Very dangerous, potentialhazards of nuclear meltdown l Low efficiency l Thermal pollution
Hydropower
l No emission of greenhouse gases and particulate matter l High efficiency and low running costs l Renewable
l Requires dams, which displaces large amounts of population. Also flood animal/plant habitats l There are few good locations for dams in the world l Completely useless in the event of drought
Geothermal Energy
l Inexpensive l Little air pollution
l Thermal pollution caused by the used hot water l Can run dry
Tidal Power
l No pollution l Renewable
l High construction costs l Few appropriate sites l Fails to meet energy demand during peak hours
Solar Energy
l Free, renewable l Available everywhere l Does not suffer from rising energy prices l No environmental problems
l Small energy output per unit area of solar cells l Inconsistent (due to rain, clouds, night etc.) l Expensive to set up solar cells
Wind Power
l Cheap, clean, renewable l Can combine with other sources, such as with solar power, because when sunny there is little wind and when windy there is little sun
l High cost of setting-up l Unpredictable
Wave and ocean current power
l If properly harnessed can provide 10% of current world electricity supply (that’s a lot!)
l Extremely high costs
For more advantages/disadvantages of each source, click here.
8.2 World Energy Sources (Jennifer and Tetsuya)
2 hoursContents
8.2.1 Identify different world energy sources.
8.2.2 Outline and distinguish between renewable and non-renewable energy sources.
8.2.3 Define the energy density of a fuel.
8.2.4. Discuss how choice of fuel is influenced by its energy density.
8.2.5 State the relative proportions of world use of the different energy sources that are available.
8.2.6 Discuss the relative advantages and disadvantages of various energy sources.
8.2.1 Identify different world energy sources.
Students should be able to recognize those sources associated with CO2 emission. Students should also appreciate that, in most instances, the Sun is the prime energy source for world energy.
For more information click here :) Also refer to Giancoli pg. 466-467
Fossil Fuel
Fossil Fuels are naturally occurring fuels formed by the remains of plants and animals from millions of years ago. They provide most of the world's energy supply. When burnt, fossil fuels release energy. They also produce: water, large amounts of carbon dioxide (CO2), carbon (soot), carbon monoxide (CO), sulphur dioxide (SO2), oxides of nitrogen, unburnt hydrocarbons and particulate matter. Therefore burning fossil fuels is a huge source of pollution.
Common Fossil fuels: Peat, coal, crude oil, oil shale, oil tar, natural gas
Refer to 8.3
Nuclear Power
There are two ways (nuclear reactions) to obtain nuclear energy: nuclear fusion and nuclear fission. Currently our technology allows us to safely use only nuclear fission. Nuclear reactions produce no greenhouse gases, but they release radioactivie substances which are highly dangerous.
Refer to 8.4.1-8.4.11
Renewable Resources
Solar Energy
Solar energy comes from our sun which creates energy from nuclear fusion (mainly of hydrogen and helium). The sun provides 90% of the thermal energy needed to heat the Earth. We can directly harvest solar energy with passive solar energy cells and photovoltaic cells; both of these methods are pollution free. The sun is also indirectly responsible for a number of energy sources, both renewable and non-renewable:
Wind power, fossil fuels, wave power, biomass, food (chemical energy) etc.
Refer to 8.4.12-8.4.14
Wind Power
Wind power is made possible by the sun.Wind occurs when currents of air move due to temperature differences. This type of power is also pollution free.
Refer to 8.4.18-8.4.20
Hydropower
Hydropower makes use of gravity. Obtaining this type of energy is also pollution free. It will be explored with more details in section 8.4.16-17 and 8.4.22
by Jennifer
8.2.2 Outline and distinguish between renewable and non-renewable energy sources.
There is a very very good link on BBC about the types of energy. The third page is about Non-renewable energy and the fourth page is about renewable energy. go to GCSE Bitesize
The other pages are good too.
A non-renewable energy source is one that is considered to be a temporary source that is depleted when it is used. (Nuclear energy could be considered a non-renewable resource however the finite amount of fissable material could last several thousand years at the current rate of usage so it is not considered a non-renewable resource. (according to the green book))
Non-renewable energy sources are for the most part fossil fuels. They are introduced in 8.2.1 above and discussed in 8.3. You can also check the green book and the following link which also has further links relating to non renewable resources. Non renewable energy sources
A natural resource qualifies as a renewable resource if it is replenished by natural processes at a rate comparable or faster than its rate of consumption by humans or other users. Renewable energy source is one that is permanent or one that can be replenished as it is used.
Renewable energy existing capacities, at end of 2006, from REN21[1]
examples
Perpetual resources that are in no danger of being used in excess of their long-term availability i.e.
Solar radiation
Tides
Winds
Hydroelectricity
Some renwewable resources must be carefully managed to avoid exceeding the environments capacity to replenish them i.e.
Geothermal power
Fresh water
Timber
Biomass
Renewable sources being developed for commercial uses i.e.
Nuclear fusion
Solar Energy
Biomass
Wind energy
Tidal energy
Wave energy
Hydro-electric Energy
Geothermal Energy
Nuclear fusion is likely to be the energy source of the future but at this stage the reaction of the fusion elements can neither be contained nor controlled.
From Wikipedia: http://en.wikipedia.org/wiki/Renewable_energy
Above shows the comparison of total solar (left), wind and geothermal energy (center) resources compared to global energy consumption (right).
From Wikipedia: http://en.wikipedia.org/wiki/Energy_transformation
The above diagram shows energy transformation in energy system language
By Tetsuya
8.2.3 Define the energy density of a fuel.
Energy density is measured in J kg–1 .
Definition: amount of potential energy stored in a fuel per unit mass or per unit volume (measured per unit volume basically for pressurized gases). The
'energy stored' is considered to be chemical potential energy.
Energy Density of a Fuel = Chemical Potential Energy/Mass
This means that the higher energy density a fuel has, the more energy is stored for the same amount of mass.
Here are some common types of fuels and their energy densities. For more types of fuels and their (possibly inaccurate) energy densities click here.
By Jennifer
8.2.4. Discuss how choice of fuel is influenced by its energy density.
The values of energy density of different fuels will be provided.
Gravimetric Energy Density and Volumetric Energy Densities of different fuels
1 Watt second is 1 joules, so 1 Watt hour which is 3600 Watt second, would be 3600J and conversely 1J is 2.7778 ×10−4 watt hour
The following table is in Watt hour per kilogram (Wh/kg) and Watt per liter (Wh/l)
It has generally been found that fossil fuels are the most cost effective (by comparing cost of production with energy density).
By Tetsuya
8.2.5 State the relative proportions of world use of the different energy sources that are available.
Only approximate values are needed.
From Wikipedia: http://en.wikipedia.org/wiki/Image:World_energy_usage_width_chart.svg
This chart shows an approximation of the world's current energy usage.
From this we can see that Hydropower is the most popular source of renewable energy. Unfortunately, it can significantly damage its surroundings (see below). New technology may allow for better hydropower standards.
By Jennifer
8.2.6 Discuss the relative advantages and disadvantages of various energy sources.
The discussion applies to all the sources identified in sub-topics 8.2, 8.3 and 8.4.
l Large energy density
l Extraction is less damaging to land than extracting fossil fuels
l Does not release carbon dioxide
l Low efficiency
l Thermal pollution
l High efficiency and low running costs
l Renewable
l There are few good locations for dams in the world
l Completely useless in the event of drought
l Little air pollution
l Can run dry
l Renewable
l Few appropriate sites
l Fails to meet energy demand during peak hours
l Available everywhere
l Does not suffer from rising energy prices
l No environmental problems
l Inconsistent (due to rain, clouds, night etc.)
l Expensive to set up solar cells
l Can combine with other sources, such as with solar power, because when sunny there is little wind and when windy there is little sun
l Unpredictable
By Jennifer